Clean room air filter system with self-supporting filter units

ABSTRACT

Clean room ceiling in which the individual filter units are suspended solely by unshared suspension assemblies so as to be self-supporting and readily installable and removable individually and free of grids and other multiple unit supporting expedients.

REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional ApplicationsSer. No. 60/029,122, filed Oct. 24, 1996, and Ser. No. 60/039,222, filedFeb. 28, 1997.

FIELD OF THE INVENTION

This application relates to construction of clean rooms, and moreparticularly HEPA, ULPA and like high efficiency air filter systems forclean rooms. Clean rooms are enclosed spaces wherein the ambient air isrepeatedly filtered to be substantially free of particulates, e.g.,installations in which air is highly filtered to maintain an absence ofparticulates larger than 0.3 micron size, with HEPA filters, or largerthan 0.12 micron size with ULPA filters. The term "HEPA" will be usedherein to refer to either or both of HEPA and ULPA filters and otherlike high efficiency filters. Clean rooms are commonly used in thepharmaceutical, medical and electronic industries.

BACKGROUND OF THE INVENTION

Typically, an array of filter units is disposed above or to the side ofa clean room. The term "clean room ceiling" herein refers to either anoverhead array, or a to-the-side, sidewall array of filter units. Ineither case the room air is collected, recycled, and brought underpressure to the filter units. A volume of air to be filtered istypically pressurized on the upstream side of the filter unit to enableflow through the filter media. The term "plenum" herein refers to thatspace in which air is at a relatively higher pressure before flowthrough the filter media than on the outlet side of the filter. In alarge filter installation the plenum is a large volume space above theclean room ceiling. In a small installation, such as a bench apparatus,the filter unit is typically combined in a housing with a fan, whichserves to pressurize the air for through-filter media flow. Theplenum-contained, pressurized air passes through the rear face of thefilter units, through the filter media within the filter units and tothe front face of the filter units for reintroduction into the cleanroom or toward the bench.

Because the filter units are of relatively limited size, a typical unitbeing only two feet by four feet, and the frequent need to cover agreatly extended area over a clean room, often the size of severalfootball fields, multiple ones of the filter units are mounted adjacentone another in a laterally and longitudinally extended array, and thearray sealed against leakage of unfiltered air from the plenum. Thefilter array mounting and sealing challenge has been met in the past byerecting extensive grids, suspended from above, onto which the filterunits are placed. These grids often take the form of troughs with theindividual filter units being fitted into a given rectangle of the gridwith a projecting portion of the filter units being immersed in a gelsealant carried in the trough. The sealant and filter unit portionscooperate to block air flow from the plenum from entering the clean roomexcept through the filter units. The grid troughs have a certain width,which increases the lateral spacing between filter units, ironicallyincreasing the paths for sideflows of unfiltered air. In addition, thetrough width reduces the proportion of filtered air area in the cleanroom ceiling, and induces turbulent air flow between the filter units,causing vibration.

Gel sealants to be effective must retain some elasticity or capacity toflow, despite years in place, so as to continually bear against thefilter unit portions in the trough despite aging of the gel andvibration of the filter units. Replacement of the HEPA filter units asthey become inefficient is a burdensome task. The individual units mustbe lifted up and away from the gelatinous mass in the troughssufficiently to clear the trough edges, tipped or somehow angled so asto pass through the grid opening defined by the troughs, and carried outof the grid. Clinging gelatinous sealant can be messy. The installationof the new filter unit repeats these steps in reverse. More gel sealantmay need to be added; these gels are quite expensive.

In U.S. Pat. No. 4,883,511 to Gustin et al, a clean room ceiling systemis shown which uses gel sealants to seal filter units held in avertically staggered array to support each other without use of a planargrid of troughs. In U.S. Pat. No. 5,329,739, the patentee Madl describesa clean room filter system in which clusters of four filter units aresupported together at the intersection of their respective corners by adisk overlapping each corner, the disk depending from a support surfacesuch as a ceiling. Gel sealant carried on sealing strips seals thefilter units against unfiltered air leakage.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a number of improvements in clean roomtechnology. The invention clean room ceilings have a less costly, moreconvenient, simpler, and more effective design. Sealant gels are nolonger necessary. Individual filter units are self-supporting, freely ofshared support with other filters. The invention does away with theentire grid structure formerly though necessary both to support and toseal the clean room ceiling filter units against sideflows of unfilteredair. All the filters are in a plane and none need be verticallystaggered as in the Gustin patent. No filter shares its support with anadjacent filter, much less three adjacent filters as in the Madl patent.In this invention the filter units themselves carry internally theirmeans of own individual support, eliminating the extensive grids usedheretofore, and obviating the need for arbitrary spacing betweenadjacent filter units now left to accommodate the filter support grid.The filter units being individually self-supporting are added into orremoved from a ceiling array without disturbing the laterally orlongitudinally adjacent filter units. The filter units are readilyshiftable into or out of position. Adjacent filter units are closertogether than in conventional clean room ceilings, increasing theproportion of the ceiling that is composed of filter units, reducing airflow incursions between the filter units, its turbulence and concomitantvibration. The invention filter units and filter unit suspensionassemblies cooperate to permit ready locking in place by simply shiftingthe filter unit into position against the installed suspension assemblyand snap-locking the filter to the support, from below, and withoutextensive screwing of threaded elements together. Conversely, the filterunit suspension assembly is simply disconnected, and from below thefilter unit, for easy removal with a disassembly feature to bedescribed. The filter units are sealed to each other across their narrowseparation. Sideflows of air along the filter units walls are blocked byan adherent, suitably self-supporting mass or web bridging the gapbetween adjacent filters and lying across any possible flow path, anexpedient made feasible by the close spacing of the filter units. Thenew filter support system is easily integrated with sprinkler systemsand ceiling lamps. Blank units (rectangular panels without filters) canbe substituted for filter units as need without changing the simplicity,which is the hallmark of the invention. Other features and advantages ofthe invention will become known from the following description.

The invention accordingly provides a clean room ceiling having multiplefilter units each comprising a unit frame and, therewithin, filtermedia, the units being suspended in place by unshared suspensioncomponents including individual ties, to be suspended freely of othersupport such as a grid or other filter units, and a tie anchoringbracket within each filter unit inward of the unit frame periphery,adjacent ones of the unit frames being sealed against air leakagebetween units.

The invention further provides a clean room filter comprising segmentedfilter media within a filter frame, and a bracket forming an anchorbetween media segments, the bracket anchor being attached to the frameand adapted to secure a tie to the filter in supporting relation,whereby the filters are self-supporting in an array of the filters.

More particularly, the invention provides a clean room filter arraycomprising a plurality of individual filter units arranged for deliveryof filtered air to a clean room, each of the individual filter unitshaving a suspension assembly unshared with any other filter unit,whereby each filter unit is shiftable to and from the arrayindependently of shifting the position or orientation of the otherfilter units or altering their respective suspension assemblies.

In this and like embodiments, generally, there is also included air flowblocking structure between adjacent filter units, typically the air flowblocking structure comprising a filter unit-supported air imperviousmass such as caulking, a web such as a tape, or other structure which isdesirably self-supporting and can be adhered in place arranged to blockair flow between adjacent filter units. The air impervious webpreferably comprises a self-supporting filter unit-adherent web, e.g.,solidified caulk compound, or a tape which can be formed in situ bypainting or otherwise, extending between adjacent filter units to blockair flow therebetween. Further, the filter units each have a faceportion facing the clean room, the mass, web or tape being adhered to oradjacent the unit face in bridging relation between adjacent filterunits to block air flow therebetween.

In a further embodiment, the invention provides a clean room filterarray comprising a laterally and longitudinally extended plurality ofindividual filter units arranged for delivery of air from a plenum to aclean room through the face of each the filter, each individual filterunit having a laterally adjacent filter unit across a gap therebetweenthrough which unfiltered air flows past the filter units, and an airimpervious mass secured across at, adjacent or in the gap to bridge thegap in air flow blocking relation. The mass suitably comprises web suchas a tape comprising a backing and an adhesive layer, the mass being,e.g., a tape sufficiently flexible to air tightly seal to itself incrossing relation, or the mass comprises a formable sealant adherent toitself and the adjacent filter units in gap sealing relation.

In a further embodiment of the invention there is provided incombination: an individual filter unit adapted for arrangement in anarray for delivery of filtered air to a clean room, and an individualfilter unit suspension assembly unshared with any other filter unit ofthe array.

In this and like embodiments typically: the filter unit comprises afilter frame, and filter media within the frame; the suspension assemblycomprises a bracket mounted to the frame and adapted for mounting thefilter unit to a support surface outside the frame; the suspensionassembly further comprises an elongated member adapted to connect thefilter unit bracket to a supporting surface in spaced relation of thefilter unit frame to the supporting surface; the filter unit framedefines a front face facing the clean room and an oppositely facing rearface, the suspension assembly comprising an elongated member extendingfrom the support surface, a bracket connected to the filter unit frameand preferably located within the plane of the filter frame, andcooperating structure on the elongated member and the bracketrespectively, the cooperating structure securing the bracket to theelongated member, whereby the elongated member extends through thefilter unit frame rear face toward but not necessarily to the filterunit frame front face; the suspension assembly elongated member extendsa predetermined distance which is suitably greater than the distancebetween the supporting surface and the filter unit frame rear face andnot substantially greater than the distance between the supportingsurface and the filter unit frame front face, whereby the elongatedmember terminates beyond frame rear face and adjacent the frame frontface, the suspension assembly bracket being mounted to the filter unitframe in a manner to intersect with the elongated member at thecooperating structure and preferably within the perimeter of the filterunit frame in some embodiments of the invention; the filter unit furthercomprises a filter media divider between separate sections of filtermedia, the suspension assembly bracket preferably being located at thedivider; the divider extends between the filter frame rear face and thefilter frame front face, having a shoulder portion, the divider shoulderportion-defined suspension assembly bracket defines a member mount, thesuspension assembly elongated member being mounted to the suspensionassembly bracket at the member mount in individual filter unitsupporting relation; there is further included a fastener fastenable tothe elongated member, the fastener blocking separation of the elongatedmember and the suspension assembly bracket in individual filter unitsupporting relation; the divider is interiorly open between the framefront face and the location of the fastener on the elongated member, thefastener being sized to be movable through the open interior of thedivider; the divider has a front face wall, and a sidewall therebetweendefining a divider open interior, the divider open interior extendingbetween its the front and rear face walls, the elongated memberextending into the open space through the divider rear face wall, afastener fastenable to the elongated member in blocking relation to themember inward of the divider rear face wall, the fastener beinginsertable or removable from the member and the divider through thedivider front face wall.

In a further embodiment, the invention provides, in combination: anindividual filter unit adapted for arrangement in an array for deliveryof filtered air to a clean room, and an individual filter unitsuspension assembly unshared with any other filter unit of the array,said individual filter unit having left and right packs of filter mediaand a rigid divider therebetween, the divider defining a suspensionassembly bracket, a suspension assembly elongated member mounted to saidsuspension assembly bracket, and a fastener fastenable to the elongatedmember to block separation of the elongated member and the suspensionassembly bracket in individual filter unit supporting relation.

In this and like embodiments, typically, the fastener comprises a lockbody, a movable latch finger mounted in the lock body, the movable latchfinger being shiftable from the lock body, and biasing structure biasingthe movable latch finger to shift from the lock body, the lock bodybeing sized to pass the assembly bracket in the unshifted condition ofthe latch but not in the shifted condition of the latch, like a snaplock; the divider has a rear face wall, an open interior, and a frontface wall, the divider front face wall being arranged to pass thefastener lock body out from the divider open interior and to give accessto the fastener for fastening or unfastening the fastener through thedivider front face wall; and the fastener latch finger is shiftedoutward against the bracket in response to the fastener lock bodypassing the divider rear face wall from within the divider openinterior.

In a further aspect of the invention, there is provided in combination:an individual filter unit adapted for arrangement in an array fordelivery of filtered air to a clean room, and an individual filter unitsuspension assembly unshared with any other filter unit of the array,each filter unit having a filter frame comprising a wall, the filterframe wall defining a suspension assembly bracket, the suspensionassembly further comprises an elongated member extending from a supportsurface to the bracket in engaging relation.

In this and like embodiments, the suspension assembly bracket furthercomprises a fastener, e.g., a separable fastener, supported by thefilter unit frame wall, the fastener being engaged with the bracket inelongated member retaining relation, whereby the filter unit frame issupported; the suspension assembly bracket comprises a flange projectingfrom the filter unit frame wall in elongated member engaging relation incooperation with the fastener; and there is further included a sealingstrip circumscribing the filter frame in adjacent filter frame engagingrelation, the bracket flange overlying the sealing strip.

In certain embodiments, the filter unit frame has a front face facingthe clean room, and includes also a resilient strip extending about thefilter unit frame rearwardly adjacent the filter unit frame front faceto leave an exposed edge margin of the filter unit frame; and in theseother embodiments there is further included in combination with anadjacent filter unit an air impervious mass, such as a web, blocking airflow between adjacent filter units, the mass being attached adjacent thefront face and the exposed edge margin of the filter unit frame.

The invention further provides a filter unit for installation in a cleanroom array of filter units, the filter unit comprising a filter frame,filter media within the frame, and a suspension assembly bracketdefining, e.g., inward of the periphery of the filter unit frame and/orwithin the plane of the filter media, a locus of attachment for anelongated member extending from a supporting surface.

In this and like embodiments, typically, the filter unit has a filtermedia divider attached to the filter unit frame, the divider having apair of spaced apertures adapted to cooperate with a pair of elongatedmembers in bracket defining relation; the filter media divider furtherincludes an additional aperture adapted to pass water-carrying conduitthrough the filter unit frame divider; the filter unit is combined withwater-carrying conduit and a sprinkler head; the filter unit frameincludes a frame wall surrounding the filter media, the frame walldefining a bracket adapted to cooperate with the elongated member infilter unit supporting relation, and the filter unit is combined with afastener engaged with the bracket, e.g., with a fastener wholly withinthe recess defined by the filter unit wall.

In a further embodiment, the invention contemplates a clean room filtersystem in which the individual filter units are each supported by theirown suspension assemblies free of any suspension support, such as a gridor disk, or other structure which is adapted or arranged to engagesimultaneously in supporting relation two or more individual filterunits.

In this and like embodiments, typically, the individual filter unitshave a frame and filter media from other portions thereof, and there isfurther included a sprinkler system having a plurality of downcomersequipped with sprinkler heads, the sprinkler system downcomers passingthrough the individual filter units through the dividers therein; theindividual filter units are shiftable to and from the system from withinthe clean room and without need of changing the suspension arrangementof the adjacent filter units, in contrast to the Madl and Gustin systemsdiscussed above.

In another aspect, the invention provides a clean room comprising anenclosed volume at least partly defined by a clean room filter arraycomprising a plurality of individual filter units and in spaced relationto a support surface, the clean room enclosed volume having airrecirculation to and from the enclosed volume, filter units of thefilter array being disposed opposite the support surface and arranged tofilter the recirculating air, the filter array filter units beingsupported by individual suspension assemblies peculiar to each filterunit, the filter units being sealed to each other against unwanted airflow therebetween.

In a highly particular embodiment, the invention provides a clean roomfilter array comprising a series of laterally and longitudinallyjuxtaposed individual and mutually independent filter units arranged tofilter air entering the clean room, each filter unit comprising agenerally rectangular frame and left and right masses of filter mediaheld within the frame, a media divider between the media masses, themedia divider having a longitudinal wall opposite each of the mediamasses and upper and lower transverse walls between the longitudinalwalls arranged such that the divider is interiorly open; individual andmutually independent suspensions for each of said filter units, eachsuspension comprising a rod extending from a support surface, a bracketdefined by a portion of the divider upper transverse wall, the bracketcomprising a wall portion surrounding an aperture in the uppertransverse wall, and a fastener coupling the rod and bracket together,the fastener comprising a nut threadedly mounted on the rod, the nuthaving a spring loaded latch finger which extends over the bracket wallportion about the aperture when the rod extends through the aperturecarrying the nut, whereby the filter unit frame is mountable to the rodby shifting the filter unit to and over the end of the rod and along therod until the nut is encountered, compressing its extending latch fingerinto said nut with the bracket until the aperture is passed whereuponthe latch finger reextends from the nut and engages the bracket againstreturn shifting of the filter frame until the latch finger is againcompressed into the nut and the nut withdrawn through the aperture, therod carrying a guide plate spaced from said bracket a distancesufficient to permit said nut to fully pass through said aperture fromwithin said divider while maintaining the filter at a common level withother filters.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further described as to an illustrative embodimentin conjunction with the accompanying drawings in which the severalFigures illustrate the invention.

FIG. 1 is a perspective, fragmentary view of a clean room ceiling filterunit array as viewed from below;

FIG. 2 is a fragmentary view of the filter array of FIG. 1, as viewedfrom above;

FIG. 3 is an axonometric view of a single filter unit before assemblywith the support rods;

FIG. 4 is a view taken on line 4--4 in FIG. 2;

FIG. 5 is a fragmentary view in section of the filter unit in analternative support embodiment;

FIG. 6 is a fragmentary view in section of a further alternative supportembodiment;

FIG. 7 is a fragmentary view like FIG. 4, but showing the fastenerremover poised to deflect the latch members on the fastener;

FIG. 8 is a fragmentary view of the filter unit array sealed with tapeand forming a clean room ceiling;

FIG. 9 is a view taken on line 9--9 in FIG. 8;

FIG. 10 is a view taken on line 10 in FIG. 9;

FIG. 11 is a fragmentary view in section of juxtaposed filters spacedand sealed;

FIG. 12 is a view of a filter and plenum combination embodiment of theinvention;

FIG. 13 is a view like FIG. 3, but of a single mounting point filterunit;

FIG. 14 is a view like FIG. 11 showing an alternative sealingarrangement;

FIG. 15 is a view of filter units suspended with an alternate suspensionassembly;

FIG. 16 is a view in section of the filter unit suspension assemblytaken on line 16--16 in FIG. 15;

FIG. 17 is a view taken on line 17--17 in FIG. 16;

FIG. 18 is a fragmentary, detail view of a filter unit having a waterconduit and a sprinkler assembly incorporated therein;

FIG. 19 is a fragmentary view in section of an alternate filter unit andsprinkler arrangement; and,

FIG. 20 is a fragmentary view in section of a further alternate filterunit and sprinkler arrangement.

DETAILED DESCRIPTION

As noted above, the invention provides an improved clean room ceiling,one in which the formerly used combined filter support and sealing gridis obviated in favor of the simple individual mounting of each filterunit by its own suspension assembly. Sealing is effected by a web ofcaulk material or tape, applied per se or formed in situ, or, ifpreferred, by other sealing techniques such as conventional gelswithout, however, the use of filter unit supporting grid troughs. Themounting and demounting of the individual filter units involves merelythe insertion of a support rod into a preformed aperture in the filterunit divider, or the filter unit wall, either of which defines thesuspension bracket, and fastening the unit in place. Or unfastening.

With reference now to the drawings in detail, in FIGS. 1-10, andparticularly FIGS. 1, 2 and 8, the invention clean room is shown at 10comprising an enclosed volume 12, and thereabove a clean room filterarray 14 comprising a plurality of individual filter units 16 arrangedfor delivery of filtered air to the clean room enclosed volume. Each ofthe individual filter units 16 has its own suspension assembly 18unshared with any other filter unit. Accordingly, each filter unit 16 isshiftable to and from the array 14 independently of shifting theposition or orientation of the other filter units, and freely of, orwithout, altering their respective suspension assemblies 18.

It will be noted the individual filter units 16 are very nearlylaterally and longitudinally abutting, thus providing little spacebetween adjacent units, especially in comparison with prior art systemsin which the filters are collectively supported by a grid structure, orother arrangement, such as corner fittings, where the mass of the filtersupport system actually increases the space between filters, increasingthe gap to be sealed and likely allowing undue air-flow relatedvibration. In the present invention the separation between adjacentfilter units 16 is minimally that amount needed for mechanicalclearance, thus increasing the filtered area in the clean room ceilingrelative to its unfiltered area over other systems.

It is generally necessary to block air flow between adjacent filters,however, in the present design if the filters are left individuallysuspended and not permanently fixed together. Thus, the presentinvention clean room filter array 14 has air flow blocking structure 20between adjacent filter units 16. In the FIGS. 8, 9 and 10 illustratedembodiment, the air flow blocking structure 20 comprises a filter unit16--supported series of air impervious webs 22 is arranged to block airflow between adjacent filter units. The webs 22 are adhered to each of apair of adjacent filter units 16, as shown, with the web edge margins 24affixed to the front face edges 26 of the filter units so that the webbridges the gap 28 between the filter units. The gap 28 is typicallysmall, e.g., less than twice the width of the filter unit wall 29,allowing for close spacing of the filter units 16, and the mentionedincrease in proportion of filtered area in an installation, particularlyover gel-dependent, grid-trough sealing systems. Each filter unit 16suitably has a strip 32 of rubber, plastic or other, preferablyelastomeric or resilient, material 33 thereon set back along the depthof the filter unit away from the filter unit front face edges 26, toprovide space for adhesion of the web 22 to the edges and/or theadjacent edge margins 24. The resilient strip 32 serves as a form ofpartial air seal between adjacent units 16 and as well as a means ofdamping vibration in the array 14, such vibration being already reducedby the immediate adjacency of the juxtaposed filter units and consequentreduced air flow turbulence between the units.

In the FIGS. 8-10 illustrated embodiment, the air flow blockingstructure 20 comprises air impervious web 22 in the form of a filterunit-adherent tape 34 extending between adjacent filter units 16 toblock air flow therebetween.

In the FIG. 11 embodiment, the web 22 is in the form of an adhesive 25held in place by a fitting 27 inserted into recess 17 between adjacentfilter units 16. In the FIG. 17 embodiment, the web 22 is in the form ofa rolled or otherwise formed caulking 31 which is inserted between theopposing filter units 16 so as to block air flow from the gap 28 intothe clean room volume 12 (FIG. 1).

Returning to FIGS. 8-10, the tape 34 may be preformed or formed in placeby painting, rolling or otherwise applying a suitably viscous paste orliquid which is film-forming upon evaporation of solvent, or by othermeans. Preferably, the tape 34 is a preformed structure typicallycomprised of one or more layers of a strong backing 36 itself made ofany suitable metal, cellulosic, or plastic material, for example, andfor each backing layer a strongly adhering layer 38 of adhesivematerial, such as isobutylene and silicone-based adhesives. Multiplelayers of these and other adhering or strengthening materials can beused. In preferred embodiments, the tape 34 runs laterally of andlongitudinally of the clean room filter array 14 matching therectilinear openings of the gaps 28. Thus deployed, tape 34 hasintersections 42 at intervals corresponding to the corners of filterunits 16. It is important to maintain the integrity of the seal at theseintersections 42. This can be done by selecting a tape 34 which isflexible enough in the backing and/or the adhesive layers 36, 38respectively to closely fit into the inevitable folds and angles of thetape as it meets at edges or passes over itself at intersections 42. Inparticular, the angle of the tape 34 in rising from the filter unit 16to cross a second segment of the tape may not be a perfect 90 degrees ifthe tape backing 36 material is not sufficiently flexible to bend andstay bent at 90 degrees. In this circumstance the adhesive layer 38volume is desirably thick or great enough to bridge the typicallytriangular volume between differently directed crossing segments of tape34; or other expedients can be used to obtain and maintain the desiredcontact and air flow imperviousness of the tape 34 at all pointsincluding tape intersections 42, such as added layers or pieces ofmaterial, compression devices, caulking, and other bonding agents, notshown.

Having detailed the sealing between filter unit 16 we will turnparticularly to FIGS. 1, 2, 3 and 4. The clean room filter array 14 of alaterally and longitudinally extended plurality of individual filterunits 16 is arranged for delivery of air from plenum 44 to the cleanroom volume 12 to the filter unit front face 46 from the filter unitrear face 48 of each filter unit 16, the individual filter units eachbeing in combination with an individual filter unit suspension assembly18 unshared with any other filter unit of the array.

Each filter unit 16 comprises a filter frame 50 having walls 29 suitablyof aluminum or other metal but possibly of wood. Within the frame 50 andbetween its rear face 48 and its front face 46 are disposed left andright hand packs 52, 54 of filter media 56, the filter media lyingwithin the filter frame walls 29. A divider 57 separates the left andright filter packs 52, 54. In the past, the function of the divider 57has been to support the filter packs 52, 54 in place and to giverigidity to the filter unit frame 50. These functions continue in theinvention filter units 16, and a new function, that of a bracket tosupport the individual filter units from individual suspensionassemblies 18, is added. Divider 57 is a box-beam configured, rigidelement which is bonded to the filter frame 50 at its opposite ends 59,61 and defines the suspension bracket 58 as will be describedhereinafter.

Each suspension assembly 18, then, comprises the bracket 58 mountedwithin the filter frame 50, the bracket being adapted for mounting itsindividual filter unit 16 to the support surface 62 outside or beyondthe frame and typically to the structural or true ceiling of the room inwhich the clean room is constructed. While the clearance between theclean room filter array 14 and the true ceiling of the surrounding roomis often great, with the present invention, lower height rooms than arenormally contemplated for clean room installation will be useful.Omitting the construction of the extensive trough grid and supportsystem as allowed the present invention permits installations in placeshitherto thought to be too low ceilinged for the old type ofinstallation, or too small to permit incurring the typical grid systemexpense.

The filter unit array 14 is surmounted by the true room ceiling, or by aceiling substitute such as constructed housing 64, providing supportsurface 62 (FIG. 2) and which with the filter unit array 14 forms theplenum 44. The filter media packs 52, 54 are open to enclosed volume 12at the front face 46 of the filter units 16 and the plenum 44 at therear face 48 of the filter units.

The suspension assembly 18 further comprises a rod 68 or other elongatedmember adapted in its length, diameter, strength and conformation toconnect the filter unit suspension bracket 58 to the support surface 62at the room ceiling or elsewhere, in spaced relation of the filter unitframe 50 to the supporting surface. The suspension assembly elongatedrod member 68 extends from the support surface 62 to the bracket 58connected to the filter unit frame 50 and preferably located within theplane of said filter media packs 52, 54, or within or adjacent the planeof the filter unit frame. The rod 68 is usefully threaded at 74 orcarries other cooperating structure with the bracket 58 for securing thebracket to the rod. Typically in the embodiment of these Figures, therod 68 extends through the filter unit frame rear face 48 and not to thefilter unit frame front face 46, so as to terminate within the filterunit frame 50 and generally within the plane of the filter media packs52, 54.

The suspension assembly bracket 58, as mounted in the filter unit frame50, intersects with the elongated rod member 68 at or near itscooperating thread structure 74 and within the perimeter of said filterunit frame. Forming the bracket 58, the divider 57 extends transverselyof the filter unit frame 50 and has a shoulder portion 75, generallycorresponding to a portion of the divider top wall 76. The dividershoulder portion 75 is locally apertured to have in this embodiment ofthe invention front and rear mounting holes 78, 80 into which the rods68 are interfittable so as to support the individual filter unit 16 byaddition of a fastener 82 to the threaded portion 74 of the rod 68. Thefasteners 82 block separation of the rods 68 from holes 78, 80 as shown.The divider 57 is interiorly open between the filter unit face 46 andlocation of said fastener 82 on rods 68, the fastener being sized to bemovable through the open interior of the divider.

Access to the fasteners 82 may advantageously be from the front face 46of the filter unit 16. For this purpose, front wall 84 of the divider 57preferably has additional holes, e.g., hole 86, in registration withholes 78, 80 and sized to pass the fasteners 82 up to the threadedportion 74 of rod 68.

With particular reference to FIG. 7, a tool 83 comprising a socket 85mounted on a shank 87 is sized to pass through hole 86 for carrying afastener 82 toward or from the rod 68 so as to have the fastenertraverse the open interior 89 of the divider 57 in a controlled mannerwhile not requiring the leaving open any great portion of the face 46 ofthe filter unit 16. The fastener 82 is thus readily accessible throughhole 86 for purposes of insertion and tightening or untightening andremoval of the fastener. It will be noted that the tool socket 85 willoverfit fastener 82 and collapse its latch fingers 92 for purposes nowto be explained.

With reference particularly to FIGS. 1, 4 and 7, in a typical clean roomfilter array installation using the invention filter units 16 andsuspensions 18, a plurality of rods 68 are suspended from the supportsurface 62. The rods 68 carry leveling plates 90 at a predetermined,measured height within the room enclosed volume 12. Plates 90 will belevel one with another and are used to line up the filter units 16 atthe same height.

Suspension fasteners 82 are designed for quick installation of thefilter array 14. Each fastener 82 comprises a fastener body 94 having,e.g. four, circumferentially distributed, vertically disposed body slots95 in each of which a shiftable latch finger 92 is carried in pivotingrelation for movement in and out of the body slots. Compression springs93 (FIG. 7) seated within slots 95 resiliently urge the fingers 92outward to a locking position as shown in FIGS. 5 and 7 unless retractedby the tool 83, for example. Shifted outward, the latch fingers 92 bearagainst the divider shoulder portion 75. The fastener 82 is threadedonto the suspension member rod 68 threaded portion 74 to a predeterminedposition, as shown. This position provides a gap 91 equal toapproximately the thickness of the divider top wall 76 between theupward edges 97 of the spring loaded fingers 92 and the downward face 99of the plates 90. In the installed condition of a filter unit 16, thedivider top wall 76 is disposed in the gap 91 between the latch fingers92 and the plate 90. The filter unit divider mounting holes 78, 80 alsofunction to close up the spring loaded fingers 92. Divider mountingholes 78, 80 are each sized to pass over the fastener 82 when thefingers are retracted, or shifted inwardly, and are desirably sized toeffect the inward shifting themselves. Easy installation of theindividual filter units 16 is thus provided as will now be described.

To install filter units 16, the suspensions 18 are arranged as justdescribed with the rods 68 depending from a support surface 62, and in apattern to register with the filter units. Plates 90 are at apredetermined, uniform level. See FIG. 2. A fastener 82 is threaded ontothe threaded portions 74 of each rod 68 to a level to establish thedesired gap 91. At each pair of suspension rods 68 a filter unit 16 ispresented, oriented to have the front face 46 facing downward (assuminga ceiling supported installation) and the rear face 48 facing upward.The filter unit divider mounting holes 78, 80 are registered with thedepending fasteners 82 and thus rods 68. The filter unit 16 is pushedupward such that the fasteners 82 pass through the divider mountingholes 78, 80. In this operation the holes 78, 80 close the fingers 92against springs 93 until the fastener 82 latch fingers pass the holesand enter the divider interior 89. The spring loaded fingers 92 thenshift outward, and as thus deployed engage the divider shoulder portion75 as the filter unit 16 is allowed to rest upon the fastener fingers.The plate 90 limits the upward movement of the filter unit 16 incoordination with the fastener 82 passage through mounting hole 78, 80.The extended fastener fingers 92 support the filter unit 16 suspended inplace. The access hole 86 is then suitably closed with a plug 100 whichis readily removable in case it is desired to demount the filter unit16. For demounting, the plug 100 is removed, the tool 83 is insertedthrough hole 86 to enclose the fastener 82 and close the fingers 92 intotheir fastener body slots 95. The fastener 82 will then pass backthrough hole 78 allowing the filter unit 16 to drop by force of gravity.It will be noted that adjacent filter units are not disturbed in theirposition or at their mountings by the addition or removal of one orseveral filter units in the just-described manner.

The filter units can have a single mounting point rather than two. InFIG. 13, filter unit 116 comprises a frame 150, filter packs 152, 154and has a divider 157. Divider 157 has a single mounting hole 178.Mounting of the filter unit 116 is as with filter unit 16 using the samesuspension assembly as previously described, except that there is asingle rod mounting locus at hole 178 and it is centered on the filterunit divider 157.

Other filter unit arrangements within contemplation of the inventioninclude self-contained units in which the filter frame and filter packsare incorporated into or combined with a hood or housing enclosurehaving is own blowers and defining its own plenum rather than using acommon plenum as in the FIG. 2 embodiment. With reference to FIG. 12 ofthe accompanying drawings, housing enclosure 110 has sidewalls 112, topwall 114 and a pair of blowers 118. A resilient strip 132 surrounds thehousing enclosure 110, for partially sealing the unit to adjacent unitsand lessening vibration of units. The filter frame and filter packs (notshown) may be unitary structures fixed within the housing enclosure 110or comprise one or more of the filter packs and filter frames such asshown in FIGS. 2, 3 and 13. The suspension arrangement is also the same,except that the housing enclosure top wall 114 defines mounting holes115, 117 rather than the divider of a filter frame.

The location and style of the fastener can be varied to meet differentneeds. For example, the fastener can be of different configurations fromthat shown in FIGS. 4 and 7, be placed in different locations, includingoutside the front face of the filter unit, or within the perimeter ofthe filter. In FIG. 5, for example, the rod 68 extends nearly the fullheight of the filter unit frame 50 and is secured adjacent hole 86 byfastener nut 111 and washer 113 acting against the front wall 84 of thedivider 57 which is suitably inwardly deflected at 109 to accommodatethe fastener nut. Plug 100 then is used to close up the opening formedby the deflection 109.

In FIG. 6, for another example, suspension rod 168 depends from asupport surface (not shown) and has its threaded portion 174 extendingthrough a hole 140 in the top wall 142 of the side 144 of the frame 150beyond the filter unit rear face 48. The rod 168 is secured by threadedconnection to a fixed nut 146 just beyond the filter media 56.

In FIGS. 15, 16 and 17, individual filter unit 216 of a series array issupported from a support surface (not shown) by four suspensions 218each comprising a rod 268 having a threaded portion 274. Filter unit 216comprises a frame 250 and has filter packs 252 and 254 disposed therein.Divider 257 fixed to frame 250 at divider ends 259, 261 separates themedia filter packs 252, 254. In this embodiment, the frame 250 has aperimetrical upper flange 251 and a perimetrical lower flange 253surrounding the frame wall 229. Upper flange 251 is pierced with holes287, 280 adjacent the corners of the frame 250. Rod 268 passes throughholes 278, 280, and, in the embodiment shown, passes through a fastener282 held in place by nut 263 by which the rod is secured to the filterframe 250. Fastener 282 has front and rear fingers 292 spring loaded asin previous embodiments of the fastener to shift outward when notblocked by the holes 278, 280 so as to support the filter unit 216 inposition against the plate 290. Strip 32 of resilient material 33 isalso provided in this embodiment, secured to the outer face of lowerflange 253. This strip 32 will abut an adjacent strip 32 on the nextfilter unit 216 in the array.

Clean room filter arrays are typically provided with lighting systemsand fire prevention systems such as sprinklers. In the presentinvention, one or more of the filter units may be replaced with a dummyunit, or a lighting unit designed to be compatible with the other filterunits in the array, being similarly suspended for example. In FIGS.18-20 typical sprinkler variations are shown for the present invention.In general, and with reference first to FIG. 18, the sprinkler supplypipe or downcomer 275 is inserted vertically through the divider 57,suitably through a space 276 located between or beside the suspensionholes (not shown) and a sprinkler head 277 secured thereto. Thedowncomer 275 is conveniently passed through a guide conduit 279 fixedin the divider 57 by clamping ring 281 secured by nuts 283 its positionbeing supported by guide ring 285. Caulking 287 about the downcomer 275provides sealing against air leakage.

In another embodiment shown in FIG. 19, a simple pipe downcomer 295which supports head 297 is inserted between left and right dividersections 357, 457, guided by ring 300, supported in place by ring 301,nuts and bolts 302 and sealed there by welding or caulking 303. In FIG.20 the pipe downcomer 304 passes through a single chamber divider 557,sealed at the top by sealing disk 305 and at the bottom by sealing disc306 and fastener 307.

There is accordingly provided in accordance with the invention cleanroom ceilings of a less costly, more convenient, simpler, and moreeffective design. Sealant gels are no longer necessary. Individualfilter units are self-supporting, freely of shared support with otherfilters. Eliminated is the entire grid structure of the prior artformerly thought necessary both to support and to seal the clean roomceiling filter units against sideflows of unfiltered air. All thefilters of the invention are in a plane and none need be verticallystaggered. No filter shares its support with any filter, much less withthree adjacent filters. The invention filter units themselves carryinternally or externally but automatically their means of own individualsupport, not only eliminating the extensive grids used heretofore, butalso obviating the need for arbitrary spacing between adjacent filterunits left to accommodate the filter support grid in previously knownclean room ceilings. The filter units, being individuallyself-supporting, are added into or removed from a ceiling array withoutdisturbing the laterally or longitudinally adjacent filter units. Thefilter units are readily shiftable into or out of position. Adjacentfilter units are closer together than in conventional clean roomceilings, increasing the proportion of the ceiling that is composed offilter units, reducing air flow incursions between the filter units, itsturbulence and concomitant vibration. The invention filter units andfilter unit suspension assemblies cooperate to permit ready locking inplace by simply shifting the filter unit into position against theinstalled suspension assembly and snap locking the filter to thesupport, from below, and without extensive screwing of threaded elementstogether. Conversely, the filter unit suspension assembly is simplydisconnected, and from below the filter unit, for easy removal with adisassembly feature to be described. The filter units are sealed to eachother across their narrow separation. Sideflows of air along the filterunits walls are blocked by an adherent, suitably self-supporting mass orweb bridging the gap between adjacent filters and lying across anypossible flow path, an expedient made feasible by the close spacing ofthe filter units. The new filter support system is easily integratedwith sprinkler systems and ceiling lamps. Blank units (rectangularpanels without filters) can be substituted for filter units as needwithout changing the simplicity which is the hallmark of the invention.

What is claimed is:
 1. A clean room filter array comprising a pluralityof self-supporting individual filter units arranged for delivery offiltered air to a clean room, each said individual filter unitcomprising a frame and filter media fixed relative to said frame, eachsaid filter unit having an individual suspension assembly suspendingsaid filter unit from within said frame and unshared with any otherfilter unit, whereby each filter unit of relatively fixed frame andfilter media is shiftable to and from said array independently ofshifting the position or orientation of the other filter units oraltering their respective individual suspension assemblies.
 2. The cleanroom filter array according to claim 1, in which each said individualsuspension assembly comprises a bracket connected within said frame andan elongated member coupled to said bracket, said elongated memberextending from said bracket to a support to individually suspend saidfilter unit by its said bracket.
 3. The clean room filter arrayaccording to claim 1, including also air flow blocking structurecomprising a filter unit-supported air impervious web arranged to blockair flow between adjacent filter units.
 4. The clean room filter arrayaccording to claim 3, in which said air impervious web comprises afilter unit-adherent tape extending between adjacent filter units toblock air flow therebetween.
 5. The clean room filter array according toclaim 4, in which said filter units each have a face portion facing theclean room, said tape being adhered to said face in bridging relationbetween adjacent filter units to block air flow therebetween.
 6. A cleanroom filter array comprising a laterally and longitudinally extendedplurality of individually self-supporting filter units each comprising aframe, an individual suspension for suspending each said filter unitfrom within its said frame, and filter media fixed within said frame andarranged for delivery of air from a plenum to a clean room through theface of each said filter unit, each said individual filter unit having alaterally adjacent filter unit across a gap therebetween through whichunfiltered air flows past said filter units, and a filterframe-supported air impervious mass secured across said gap in air flowblocking relation, whereby each said filter unit of relatively fixedframe and filter media is shiftable to and from said array independentlyof shifting the position or orientation of the other filter units oraltering their respective individual suspension assemblies.
 7. The cleanroom filter array according to claim 6, in which said mass comprises aweb having a backing and an adhesive layer, said webs being sufficientlyflexible to air tightly seal said webs to each other in web-crossedrelation.
 8. The clean room filter array according to claim 6, in whichsaid filter media in each said individual filter unit is divided intoseparate packs, an individual suspension bracket is located between saidseparate media packs, and said individual suspension further comprisesan elongated member coupled to said bracket, said elongated memberextending from said bracket to a support to individually suspend saidfilter unit by its said bracket.
 9. In combination: an individual filterunit comprising a frame and filter media relatively fixed within saidframe, said filter unit being adapted for arrangement in an array fordelivery of filtered air to a clean room, and an individual filter unitsuspension assembly adapted for suspending said filter unit from withinits said frame unshared with any other filter unit of the array foradding or removing said individual filter units of relatively fixedframe and filter media from an array without disturbing laterally orlongitudinally adjacent filter units.
 10. The combination according toclaim 9, in which said filter unit suspension assembly comprises abracket for suspending said filter unit from within said frame, andadjacent separated filter media packs within said frame, said bracketbeing located between said separated filter media packs.
 11. Thecombination according to claim 10, in which said filter unit furtherincludes a divider mounted to said frame between said adjacent separatedfilter media packs, said suspension assembly bracket being defined bysaid divider and adapted for mounting said filter unit to a supportoutside said frame.
 12. The combination according to claim 11, in whichsaid suspension assembly further comprises an elongated member adaptedto connect said filter unit bracket to said support surface in spacedrelation of said filter unit frame to said support surface.
 13. Thecombination according to claim 9, in which said filter unit framedefines a front face facing said clean room and an oppositely facingrear face, said suspension assembly comprising an elongated membersupported from a support surface, a bracket for suspending said filterunit from within said frame, said bracket being connected to said filterunit frame, and cooperating structure on said elongated member and saidbracket respectively for coupling said bracket to said elongated member,whereby said elongated member extends through said filter unit framerear face toward said filter unit frame front face in the coupledcondition of said elongated member and said bracket.
 14. The combinationaccording to claim 12, in which said filter unit filter media is dividedinto separate sections, and including also a filter media dividerbetween separate sections of filter media, said suspension assemblybracket being located at said divider.
 15. The combination according toclaim 14, in which said divider extends between said filter frame rearface and said filter frame front face, said divider having a shoulderportion, said divider shoulder portion defining said suspension assemblybracket.
 16. The combination according to claim 15, in which saiddivider shoulder portion-defined suspension assembly bracket defines anelongated member mount, said suspension assembly elongated member beingmounted to said suspension assembly bracket at said member mount inindividual filter unit supporting relation.
 17. The combinationaccording to claim 16, including also a fastener fastenable to saidelongated member, said fastener blocking separation of said elongatedmember and said suspension assembly bracket in individual filter unitsupporting relation.
 18. The combination according to claim 17, in whichsaid divider is interiorly open between the frame front face and thelocation of said fastener on said elongated member, said fastener beingsized to be movable through the open interior of said divider.
 19. Thecombination according to claim 14, in which said divider has a frontface wall, and a rear face wall and a sidewall therebetween defining adivider open interior, said divider open interior extending between itssaid front and rear face walls, said elongated member extending intosaid open space through said divider rear face wall, a fastenerfastenable to said elongated member in blocking relation to said memberinward of said divider rear face wall, said fastener being removablefrom said member and said divider through said divider front face wall.20. The combination according to claim 19, in which said fastenercomprises a lock body, a movable latch mounted in said lock body andshiftable outward from said lock body, and biasing structure biasingsaid latch outward from said body, said lock body being sized to passthrough said bracket aperture in the inward condition of said latch butnot the outward condition of said latch.
 21. In combination: anindividual filter unit adapted for arrangement in an array for deliveryof filtered air to a clean room, and an individual filter unitsuspension assembly unshared with any other filter unit of the array,said individual filter unit having left and right packs of filter mediaand a rigid divider therebetween, said divider defining a suspensionassembly bracket, a suspension assembly elongated member mounted to saidsuspension assembly bracket, and a fastener fastenable to said elongatedmember to block separation of said elongated member and said suspensionassembly bracket in individual filter unit supporting relation, saidfastener comprising a lock body, a movable latch finger mounted in saidlock body, said movable latch finger being shiftable from said lockbody, and biasing structure biasing said movable latch finger to shiftfrom said lock body, said lock body being sized to pass said assemblybracket in the unshifted condition of said latch but not in the shiftedcondition of said latch.
 22. The combination according to claim 21, inwhich said divider has a rear face wall, an open interior, and a frontface wall, said divider front face wall being arranged to pass saidfastener lock body out from said divider open interior and to giveaccess to said fastener for fastening or unfastening the fastenerthrough said divider front wall.
 23. The combination according to claim22, in which said fastener latch finger is shifted outward against saidbracket in response to the fastener lock body passing the divider rearface wall from within said divider open interior.
 24. The combinationaccording to claim 9, in which said filter unit frame has a front facefacing said clean room, and including also a resilient strip extendingabout said filter unit frame rearwardly adjacent said filter unit frontface to leave an exposed edge margin of said filter unit frame.
 25. Thecombination according to claim 9, further in combination with anadjacent filter unit, and including also an air impervious mass blockingair flow between adjacent filter units.
 26. A filter unit forinstallation in a clean room array of filter units, said filter unitcomprising a filter frame, filter media within and fixed relative tosaid frame, and a suspension assembly for suspending said filter unitfrom within its said frame from a supporting surfaces, said suspensionassembly being unshared with another filter unit for adding to orremoving said filter unit from an array of filter units with its saidframe and filter media fixed relative to each other and withoutdisturbing other filter units in said array.
 27. The filter unitaccording to claim 26, in which said filter unit suspension assemblycomprises a bracket attached to said filter unit frame, said brackethaving a pair of spaced apertures adapted to cooperate with a pair ofsaid elongated members in suspension defining relation.
 28. The filterunit according to claim 27, in which said bracket comprises a filtermedia divider, said divider further including an additional apertureadapted to pass water-carrying conduit through said divider.
 29. Thefilter unit according to claim 28, in combination with water-carryingconduit and a sprinkler head.
 30. A clean room filter system in whichthe individual filter units each comprise a frame and filter mediawithin and fixed relative to said frame, each said filter unit beingsupported by its own suspension assembly from a support surface, saidsuspension assembly being free of simultaneously engaging two or moreindividual filter units, whereby said filter unit is added to or removedfrom an array of filter units with its said frame and filter media fixedrelative to each other and without disturbing other filter units in saidarray.
 31. In combination: The clean room filter system according toclaim 30, and a sprinkler system having a plurality of downcomersequipped with sprinkler heads.
 32. The clean room filter systemaccording to claim 30, in which said individual filter units areshiftable to and from the system from within the clean room and withoutneed of changing the suspension arrangement of adjacent filter units.33. A clean room comprising an enclosed volume at least partly definedby a clean room filter array comprising a plurality of individual filterunits comprising a frame and within said frame and fixed relativethereto filter media, said clean room enclosed volume having airrecirculation to and from the enclosed volume through said filter arrayarranged to filter the recirculating air, said filter array units beingsupported by individual suspension assemblies peculiar to each filterunit so that each individual filter unit is shiftable to and from saidclean room filter array from within said clean room without changing thesuspension arrangement of an adjacent filter unit or the fixed relationof said filter frame and said filter media, said filter units beingsealed to each other against unwanted air flow therebetween.
 34. A cleanroom filter array comprising a series of laterally and longitudinallyjuxtaposed individual and mutually independent filter units arranged tofilter air entering said clean room, each said filter unit comprising agenerally rectangular frame and left and right masses of filter mediaheld within said frame, a media divider between said media masses, saidmedia divider having a longitudinal wall opposite each of said mediamasses and upper and lower transverse walls between said longitudinalwalls arranged such that the divider is interiorly open; individual andmutually independent suspensions for each of said filter units, eachsaid suspension comprising a rod extending from a support surface, abracket defined by a portion of the divider upper transverse wall, saidbracket comprising a wall portion surrounding an aperture in said uppertransverse wall, and a fastener coupling said rod and bracket together,said fastener comprising a nut threadedly mounted on said rod, said nuthaving a spring loaded latch finger which extends over said bracket wallportion about said aperture when said rod extends through said aperturecarrying said nut, whereby said filter unit frame is mountable to saidrod by shifting the filter unit to and over the end of the rod and alongthe rod until the nut is encountered, compressing its extending latchfinger into said nut with the bracket until the aperture is passedwhereupon the latch finger reextends from the nut and engages thebracket against return shifting of the filter frame until the latchfinger is again compressed into the nut and the nut withdrawn throughthe aperture, said rod carrying a guide plate spaced from said bracket adistance sufficient to permit said nut to fully pass through saidaperture from within said divider.